ScriptKit: add getHelpHandout/getDevHandout, handoutLink anchor support

- ScriptKit.getHelpHandout(scriptName) — returns cached help handout object
- ScriptKit.getDevHandout(scriptName) — returns cached dev handout object
- Handouts cached at registration and generation time (no repeated findObjs)
- html.handoutLink(text, id, style, anchor) — optional 4th param appends /#anchor to URL